Direct effect of NAADP on [Ca2+]i mobilization. (A) Representative plot of NAADP-AM–induced Ca2+ mobilization in EA.hy926 cells. (B) Increase in F/F0 in cells stimulated with NAADP-AM compared with cells stimulated with vehicle alone (control). Cells were stimulated with 100μM TMPH after microinjection with (C) vehicle alone or (D) inactivating concentrations of NAADP. Increase in F/F0 in response to TMPH (E) and 2 U/mL of thrombin (F) in cells microinjected with the inactivating concentration of 500μM NAADP compared with cells microinjected with vehicle alone. Where applicable, error bars represent SEM; n = 3 independent experiments; *P < .05 by Student t test.